The invention relates to a new method for preparing completely soluble microgranules prepared from extracts or solutions of active principles; these microgranules are intended to be used as they are for the reconstitution of solutions or to be incorporated into various galenic forms.
The administration and the use of extracts of active principles, especially of natural origin, in the form of Essential Oils, of solvent extraction solutions pose problems at various levels during use:
incomplete dissolution PA1 difficulty of precise proportioning PA1 masking of taste PA1 inappropriate galenic presentation PA1 first, in preparing an extract of an active principle in a solvent medium; PA1 then, in depositing this extract on the internal and external walls of a microporous carrier insoluble in the solvent medium, provided in the form of microgranules, having a specific surface area of at least 0.50 m.sup.2 /g; PA1 and in drying the impregnated granular carrier obtained; PA1 then, in coating the impregnated walls of the microporous carrier with a film-forming polymer; characterized in that the microporous carrier is a soluble dietary fibre based on a polymer selected from the group comprising inulin and oligofructoses and fructo-oligosaccharides, on their own or mixed. PA1 in a first instance, in preparing extracts of plant, animal or other origin, or solutions of active principles; PA1 in a second instance, in impregnating the microgranules whose specific surface area of at least 0.50 m.sup.2 /g provides optimum impregnation, these microgranules being insoluble in the extracts or solutions of active principles; PA1 in a third instance, in evaporating the solvent by drying, the substances in the extract or the solution of active principles remaining absorbed in the microscopic structure of the microgranular carrier; PA1 and finally, in coating the microgranule obtained with a film of polymers allowing it to offer stability over time inside the galenic form which will carry it during its administration, and also to be able to offer gradual release of the active principles retained, through the film of polymers. PA1 the active principle is an extract of plants or of a portion of plants; PA1 the solvent medium consists of a solvent from the group comprising water, ethanol, acetone, dichloromethane; PA1 the microporous carrier is a microgranule obtained by spray-drying or by wet granulation; PA1 the spray-dried microgranule is based on soluble fibres which can be combined with other substances such as polyalcohols (sorbitol, xylitol, mannitol), polyols (maltodextrins and the like), or fatty substances; PA1 the extract is deposited on the walls by wet granulation and the drying is carried out with hot air; PA1 the film-forming polymer is a compound which is soluble in the gastrosoluble (hydroxypropylmethylcellulose) or gastro-resistant (hydroxypropylmethylcellulose phthalate) digestive system; PA1 the film-forming polymer is pulverized in a turbine or in a fluidized bed. PA1 G: glucosyl unit PA1 F: fructosyl unit PA1 n: number of bound fructosyl units (n greater than 2) PA1 DP: degree of polymerization varying from 2 to 60 PA1 Bond of the .beta.(1-2) type PA1 G: glucosyl unit PA1 F: fructosyl unit PA1 n and m: number of bound fructosyl units (n greater than 2) PA1 DP: degree of polymerization varying from 2 to 20 PA1 The oligofructoses contain molecules of the GFn type and of the Fm type PA1 Bond of the .beta.(1-2) type PA1 sugars PA1 derivatives of sugars: ester hydrolysates, alcohols, and the like PA1 lipophilic derivatives, waxes, polymers, and the like polysaccharides and hydrolysates PA1 proteins PA1 lubricants, opacifiers colouring pigments PA1 Inulin and the oligofructoses which are dietary fibres are not significantly hydrolysed during passage through acidic medium in the stomach. The enzymes in the body which are present in the small intestine, of the sucrase-maltase type, abundantly present in the intestine, have no hydrolytic action on the bonds of the units forming these fibres, causing no increase in glycaemia and in the level of insulin in the blood. As such, these fibres may be used in the diet intended for diabetics. PA1 Inulin and the oligofructoses are rapidly fermented by the intestinal flora in the colon. The carbohydrates are metabolized to fatty acids with a small number of carbons (propionic acid, lactic acid, butyric acid and the like), and to a gas. PA1 The process of controlled disintegration, fibres metabolized "in fine", makes it possible to obtain an active principle-fibre bond which is present throughout the course of digestive assimilation, strengthened by the coating of polymer films, thus offering increased bioavailability, and specific. PA1 Low calorific value: inulin 1.0 kcal/g against 4.0 kcal/g for carbohydrates inulin 1.0 kcal/g against 2.40 kcal/g for polyols oligofructose 1.5 kcal/g against 4.0 kcal/g for carbohydrates oligofructose 1.5 kcal/g against 2.40 kcal/g for polyols PA1 The low degradation of these fibres, providing no glycaemic and insulin response in the blood, makes these fibres a specific carrier in the diet intended for diabetic pathologies. PA1 Stimulation of bifidus: the degradation of the fibres in the colon stimulates the metabolism of bifidobacteria.
The production, in dry form, of these different extracts of active principles involves, for the majority, methods using a substantial supply of heat; nebulization-spray-drying, evaporation under vacuum or otherwise, recovery from grinding or micronization, these various operations being capable of causing substantial adverse modifications. The dry forms of these various extracts which are thus obtained are subjected to adverse modifications of active principles which are linked to high hygroscopicity due to the increases in specific surface area induced by the physical treatments cited.
There has for example been proposed in the document EP-A-0,524,484 a powder for preparing instant drinks which is obtained by aqueous dissolution of tea extracts and of an inulin carrier, the mixture then being dried, and then spray-dried.
Even if a low-calorie composition is obtained by virtue of the degradation of the carrier into fructose units, its preparation requires a large volume of inulin for a given quantity of extract, which contributes towards increasing the cost of the formulation. In addition, the thermal energy released during the phase for spray-drying the powder once the active principle is attached to the inulin leads to the said active principle being thermally degraded, which excludes the use of heat-sensitive active principles. Moreover, the method used excludes the incorporation of any water-insoluble substance, in particular volatile substances, in particular flavourings and essential oils, which will be partially or completely evaporated during the spray-drying process.